Why do all the CSL like carbon boxes ditch the MAF ?

[Rombbb]

Is it because of the unrestricted wide open box, while MAF sensors require a smaller funnel to measure accurately ?

The rudimentary form of engine management via Alpha N tunes seems a step back from the more granular OEM method of simply measuring mass airflow.

The Evolve CSL box does make the best sound. Is there no way to get best of both worlds ? Like fabricating a MAF into it and keeping stock ECU ?

Or maybe another brand that keeps the MAF ? (couldn't find any)

Alternative is the Eventuri cone filter, but that seems a compromise between OEM and Evolve.

 

[BTZ461]

Consider the TMS CSL airbox, a fraction of the cost of the Evolve unit. From memory around $1500US Options other than Alpha N available too. And the Karbonnius unit is worthy of consideration also.

 

[AndyBeech]

Is it because of the unrestricted wide open box, while MAF sensors require a smaller funnel to measure accurately ?

The rudimentary form of engine management via Alpha N tunes seems a step back from the more granular OEM method of simply measuring mass airflow.

The Evolve CSL box does make the best sound. Is there no way to get best of both worlds ? Like fabricating a MAF into it and keeping stock ECU ?

Or maybe another brand that keeps the MAF ? (couldn't find any)

Alternative is the Eventuri cone filter, but that seems a compromise between OEM and Evolve.

I think you have to remember the CSL airbox was designed for a CSL with CSL mapping with the correct sensors installed to subsitute for a lack of a MAF sensor. So it had a MAP and IAT sensors with a custom map which avoided the need for Alpha-N. It's made backwards compatible for our cars and M3's so is a bit of 'bodge' in terms of the mapping (hence Alpha-N) but I don't think it's too bad if you speak to some of the guys running them, any issues have been pretty much ironed out by now. The only other thing to consider is we use a different DME as well so any map will have to be specific to that rather than a generic M3 one.

The new Turner Motorsport airbox mentioned seems worth considering cost wise though compared to others available if you do go down that route. There is no alternative unfortunately the only way you can keep the MAF is to use the Eventuri / Gruppe M solution.

 

[beanie]

I expect a MAF solution for the csl intake size was either not available/accurate using off the shelf components and/or was too costly to develop for such a low volume car hence bmw moving to a MAP setup. It’s also possible that they felt it simply wasn’t the best solution for the car.

Regardless, if you want an airbox then it’s the ‘compromise’ you have to make, however, with a good map I doubt you’ll notice any difference in drivability.

 

[RedUn]

MAFs are restrictive hence avoiding them.

The CSL isn't the only car to come from the factory with no MAF and instead use speed density mapping

 

[Rombbb]

Thanks for all the anwers !

The TMS seems not in stock anymore, but I did find several carbon boxes that allow for the MAF to be maintained. Going that route. Am not in it for the power gain, only the intake noise.

This one isa bit more expensive than the Eventuri (USD 1350,- vs 950,-) but you get a genuine box instead of a fancy inverted cone filter and hopefully, if it's true that carbon resonates the intake air, then the sound will be better :

https://www.ebay.nl/itm/BMW-M3-E46-Carbon-Airbox-Carbonfibre-airbox-einteilige-Box-fur-LMM-S54-Motor/233053334201?hash=item36430faab9:g:GzoAAOSwlV9WRYkU

German seller has good reviews and a lot of cool parts for sale.

Or this one, but double the price (ex shipping) and for me on the other side of the pond, plus in a forum someone mentioned the fitment was not good and it took 2 months for delivery :

http://store.motorsportsconcepts.com/carbon-airboxes/s54-cf-airbox-e46-m3-z4m-maf.html

 

[RedUn]

If you just want the noise then go for one of the eventuri or gruppem ones? If you going airbox then go fully blown airbox with alpha n, it's not that much more and you'll have the noise and some extra power 8)

 

[Rombbb]

If you just want the noise then go for one of the eventuri or gruppem ones? If you going airbox then go fully blown airbox with alpha n, it's not that much more and you'll have the noise and some extra power 8)

Yeah probably best, but read on several places that the evneturi is in between OEM and CSL box sound wise. Possibly still gonna try and make a box with MAF work.

 

[PDJ]

Has any one just fitted a black plate and an ITG type filter
Below is a picture/sketch of a back plate

 

[AndyBeech]

Has any one just fitted a black plate and an ITG type filter
Below is a picture/sketch of a back plate

E4FA6F4D-F97D-4949-8514-8825578A2CC8.png

I sincerely hope not! Velocity stacks would be the closest comparison and not read great things about those tbh.

Good luck with your plan Rombbb be interested to know how it works out but as Red says, if your spending that much I’d do it properly personally. It isn’t a usual solution and there is generally a reason for that would be my logic!

 

[PDJ]

I sincerely hope not! Velocity stacks would be the closest comparison and not read great things about those tbh.

Good luck with your plan Rombbb be interested to know how it works out but as Red says, if your spending that much I’d do it properly personally. It isn’t a usual solution and there is generally a reason for that would be my logic!

Not doing it to my car I removed the groupm intake and returned it to the standard air box

But that was what was on my Ford Duratec fitted in my Westfield along with tapered throttle bodies

 

[Rombbb]

Good luck with your plan Rombbb be interested to know how it works out but as Red says, if your spending that much I’d do it properly personally. It isn’t a usual solution and there is generally a reason for that would be my logic!

Thanks !

Will post the outcome, still on the fence what to do. It indeed is all very costly. Luckily BTC is going nicely ;-)

Thing is, of course there's an argument to say that the vast majority must have a point, but at the same time you hardly hear any of the negatives of running an Alpha N tune and that could either be because A. indeed is's just a good setup or B. this sub-optimal solution was just sold well by tuners and mixed with a bit of herd behaviour it became a kind of self-fulfilling prophecy in that something that was originally meant as a kind of semi-limb mode has now become the de facto optimal performance mode, which could result in any flaws, or longer term effects, becoming overlooked.

I'm not saying on or the other, but in general I do have more faith in the BMW engineering dept than smaller tuners. I know their objectives are not comparable, one has to consider environment conditions, emissions, sound and other regulations and the other can just focus on pure performance figures. But still, just call me a bit sceptical

 

[RedUn]

Good luck with your plan Rombbb be interested to know how it works out but as Red says, if your spending that much I’d do it properly personally. It isn’t a usual solution and there is generally a reason for that would be my logic!

Thanks !

Will post the outcome, still on the fence what to do. It indeed is all very costly. Luckily BTC is going nicely ;-)

Thing is, of course there's an argument to say that the vast majority must have a point, but at the same time you hardly hear any of the negatives of running an Alpha N tune and that could either be because A. indeed is's just a good setup or B. this sub-optimal solution was just sold well by tuners and mixed with a bit of herd behaviour it became a kind of self-fulfilling prophecy in that something that was originally meant as a kind of semi-limb mode has now become the de facto optimal performance mode, which could result in any flaws, or longer term effects, becoming overlooked.

I'm not saying on or the other, but in general I do have more faith in the BMW engineering dept than smaller tuners. I know their objectives are not comparable, one has to consider environment conditions, emissions, sound and other regulations and the other can just focus on pure performance figures. But still, just call me a bit sceptical

If you go for a box with a MAF or go for a box with no MAF, either way your relying on some small company to tune your car?

Be interested to see what you come up with

 

[ph001]

Has any one just fitted a black plate and an ITG type filter
Below is a picture/sketch of a back plate

E4FA6F4D-F97D-4949-8514-8825578A2CC8.png

Although that kind of setup is typically quite good for top end power the torque curve is pretty awful, particularly at low and mid revs. The Z4 runs a dual DISA setup to tune the inlet manifold length for optimal torque.

 

[Rombbb]

PDJ
Not doing it to my car I removed the groupm intake and returned it to the standard air box

Out of curiosity, why are you going back to stock if I may ask ?

 

[Rombbb]

If you go for a box with a MAF or go for a box with no MAF, either way your relying on some small company to tune your car?

Be interested to see what you come up with

Idea is to keep the MAF in the exact same position and housing diameter so to avoid any tuning at all.

Very interesting and knowledgeable answer from Pokebridges from Severn Tuning on the Alpha N and sensitivity of MAF's in sister thread on zpost : https://www.zpost.com/forums/showthread.php?t=1786101

He is one of the few that tunes the z4m ECU instead of the easy Alpha N 'fix' (but still I prefer no tuning at all, not doing it for the HP's)

 

[mmm-five]

If you go for a box with a MAF or go for a box with no MAF, either way your relying on some small company to tune your car?

Be interested to see what you come up with

Idea is to keep the MAF in the exact same position and housing diameter so to avoid any tuning at all.

Very interesting and knowledgeable answer from Pokebridges from Severn Tuning on the Alpha N and sensitivity of MAF's in sister thread on zpost : https://www.zpost.com/forums/showthread.php?t=1786101

He is one of the few that tunes the z4m ECU instead of the easy Alpha N 'fix' (but still I prefer no tuning at all, not doing it for the HP's)

If you're doing it purely for the noise/looks, then won't you risk EML lights and running issues with different air pressure/volume coming in than the stock ECU fuel/air map is expecting?

So you may still need to 'tune' the ECU to get back your 'normal' performance.

 

[RedUn]

If you go for a box with a MAF or go for a box with no MAF, either way your relying on some small company to tune your car?

Be interested to see what you come up with

Idea is to keep the MAF in the exact same position and housing diameter so to avoid any tuning at all.

Very interesting and knowledgeable answer from Pokebridges from Severn Tuning on the Alpha N and sensitivity of MAF's in sister thread on zpost : https://www.zpost.com/forums/showthread.php?t=1786101

He is one of the few that tunes the z4m ECU instead of the easy Alpha N 'fix' (but still I prefer no tuning at all, not doing it for the HP's)

If you're doing it purely for the noise/looks, then won't you risk EML lights and running issues with different air pressure/volume coming in than the stock ECU fuel/air map is expecting?

So you may still need to 'tune' the ECU to get back your 'normal' performance.

I was thinking the exact same thing, unless the carbon box is the exact same size as the oem one and flows identically then it'll need a tune. Changing before the maf the maf can measure any differences but after it's not going to know is it?

Interesting response on zpost, what's the bypass valve diameter on a turbo car got to do with the intake on a naturally aspirated car? An airline can deliver 150psi but you wouldn't want to trade your mouth for one when going for a run would you?

Secondly MAFs are restrictive by design, have a look through one? Most High rpm high bhp per litre engines have no MAFs.

Fully get your view though, I'm the same I'd prefer to keep the mapping oem with the oem sensors etc hence running an eventuri whilst I work out what I'm doing airbox and cam wise

 

[Rombbb]

Idea is to keep the MAF in the exact same position and housing diameter so to avoid any tuning at all.

Very interesting and knowledgeable answer from Pokebridges from Severn Tuning on the Alpha N and sensitivity of MAF's in sister thread on zpost : https://www.zpost.com/forums/showthread.php?t=1786101

He is one of the few that tunes the z4m ECU instead of the easy Alpha N 'fix' (but still I prefer no tuning at all, not doing it for the HP's)

If you're doing it purely for the noise/looks, then won't you risk EML lights and running issues with different air pressure/volume coming in than the stock ECU fuel/air map is expecting?

So you may still need to 'tune' the ECU to get back your 'normal' performance.

I was thinking the exact same thing, unless the carbon box is the exact same size as the oem one and flows identically then it'll need a tune. Changing before the maf the maf can measure any differences but after it's not going to know is it?

Interesting response on zpost, what's the bypass valve diameter on a turbo car got to do with the intake on a naturally aspirated car? An airline can deliver 150psi but you wouldn't want to trade your mouth for one when going for a run would you?

Secondly MAFs are restrictive by design, have a look through one? Most High rpm high bhp per litre engines have no MAFs.

Fully get your view though, I'm the same I'd prefer to keep the mapping oem with the oem sensors etc hence running an eventuri whilst I work out what I'm doing airbox and cam wise

The idea was to keep it as similar as possible, but you're right, the shape and size of the box is itself a factor, which I conveniently disregarded a bit, so even with the same MAF housing size and position as stock there will be pressure difference between the boxes, influencing the mixture.

On the turbo analogy, I guess he meant that two 1 inch ports can allow for a lot of air / pressure, to emphasize that a 3,5 inch MAF housing isn't all that restrictive. But maybe it's apples and oranges. Another forum member heard from JC Racing that a factory tuned GT car got like 400bhp with stock intake, further indicating that it's pretty capable.

Personally (as relative) layman I'd say that the stock design also seems more optimal in that air comes in at the middle, allowing the first and last cilinders to draw an equal amount of air. With the CSL box the air comes in from the front which seems to disadvantage the cilinders at the back if most air gets to the first ones first. But that just me hypothesizing. BMW did put that design on their top model so it must be good for something. Also trust the OEM setup to be more watertight in a thunderstorm compared to a cone with a scoop directed to it. Water can act in unexpected ways.

Eventuri may be the best option after all. Am in contact with that German E-bay seller who does custom carbon. Depending on price may go for a box with as close as OEM dimensions as possible. Maybe combined with the Eventuri. Really dig that CSL intake sound

 

[pokeybritches]

Interesting response on zpost, what's the bypass valve diameter on a turbo car got to do with the intake on a naturally aspirated car? An airline can deliver 150psi but you wouldn't want to trade your mouth for one when going for a run would you?

Not sure what point you are making about an airline delivering 150 psi. I was providing a related example of how little the 3.5 inch housing restricts airflow- a 911 Turbo can move 700 horsepower worth of air with 1/6 the piping. This is mass flow, not just line pressure. By the way, I also use a 3.5” MAF housing to make the 700 horsepower, and the MAF sensor setup is draw through (non-pressurized side of the turbo compressor).

On the turbo analogy, I guess he meant that two 1 inch ports can allow for a lot of air / pressure, to emphasize that a 3,5 inch MAF housing isn't all that restrictive.

Correct.

Secondly MAFs are restrictive by design, have a look through one? Most High rpm high bhp per litre engines have no MAFs.

Any restriction through the MAF housing is minimal. I won’t say it’s non-existent, but it is so miniscule that differences in temperature and pressure will affect an alpha-n tune to a greater degree than the MAF will restrict horsepower. I have given multiple examples of how it is not a serious restriction, including cars that make 50 bhp more than the CSL using the stock airbox, Supersprint V1 stepped headers, Schrick cams, and a MAF-based tune. Z4Ms using MAF-based tunes can have a similar specific output to the 991.2 GT3 RS, even with 1000 less rpm to work with and an engine that’s 15 years older, built to a different price point, and still compromised for street use (other than no cats in the exhaust). Now let me ask a few of questions:
- How big are the S54’s intake runners in comparison to the MAF sensor housing?
- How many intake valves are open simultaneously, drawing air from the reservoir in the intake manifold?
- When air moves to fill a vacuum, such as the vacuum created when an intake valve opens and the piston moves down the cylinder, how fast do you think air moves to fill that void?

He is one of the few that tunes the z4m ECU instead of the easy Alpha N 'fix' (but still I prefer no tuning at all, not doing it for the HP's)

Tuning does provide other benefits besides increased horsepower, including mapping accelerator pedal sensitivity. You can have normal mode behave like sport mode, and turn sport mode into a sport plus mode. Or, you can go the opposite direction and make the throttle less touchy. SAP delete, rear O2 sensor delete, cat delete, etc. are all possibilities.